Conversion of (CH.sub.3).sub.3 Al and NH.sub.3 to aluminum nitride is known: Bahr, FIAT, Rev. Ger. Sci., Inorg. Chem. II, 155 to 179 (1948). The reaction is as follows: EQU (CH.sub.3).sub.3 Al.multidot.NH.sub.3 .fwdarw. (CH.sub.3).sub.2 AlNH.sub.2 .fwdarw. CH.sub.3 AlNH .fwdarw. AlN.
There is no teaching or suggestion that the CH.sub.3 AlN intermediate was isolated or that the final reaction step was conducted in the presence of ammonia.
Laubengayer et al., J. Amer. Chem. Soc., 83, pages 542 to 546 (1961), disclose the reactions of amines at low temperatures with aluminum alkyls or alkyl aluminum chlorides to form 1:1 addition compounds. When such addition compounds having N--H and Al--R bonding are pyrolyzed, intermolecular condensation occurs, alkanes are evolved and aluminum-nitrogen polymeric products are formed. By control of the conditions of pyrolysis, the condensation results in a sequence of reactions producing amide aluminum polymers, imide aluminum polymers and, finally aluminum nitride.
Laubengayer et al., Inorg. Chem., 1, pages 632 to 637 (1962), disclose the reaction of triphenyl-aluminum and methylamine in toluene solution to form methylamine triphenylaluminum. This adduct loses benzene when heated in a vacuum and forms methylamido diphenylaluminum which in turn evolves benzene to form methylimidophenylaluminum. TriPhenylaluminum and dimethylamine react in toluene solution to form the dimethylamine triphenylaluminum complex which is heated to form dimethylamido diphenylaluminum.
Cohen et al., J. Chem. Soc., pages 1092 to 1096 (1965), disclose that ethylaluminum dichloride and diethylaluminum chloride form complexes with ammonia. There is no ammonolysis of aluminum-chlorine bonds. On heating, the complexes lose ethane and aluminum trichloride-ammonia, with the formation of aluminum-nitrogen polymers. They also disclose the reaction of (C.sub.2 H.sub.5).sub.3 Al and NH.sub.3, and conversion of the product to C.sub.2 H.sub.5 AlNH which is described as polymeric and insoluble in organic solvents.
Interrante, in a meeting of the Materials Research Society, Apr., 1986, at Palo Alto, Calif., disclosed the conversion of C.sub.2 H.sub.5 AlNH to aluminum nitride in the presence of ammonia. The aluminum nitride produced with ammonia contained less carbon than that formed without it. Interrante also disclosed that C.sub.2 H.sub.5 AlNH is converted to aluminum nitride at 300.degree. C. to 900.degree. C. with retention of morphology.